1. Gary Deckard Informatics 501 2 September 2014

2.  Treatise on complex systems observations in behavioral sciences which discusses relevance to complex systems in the social, biological and physical sciences  Four Sections to the article  Frequency with which complexity takes hierarchal form  Structure vs. evolution of a complex system  Nearly decomposable systems  Relation between complex systems and their descriptions  Central theme of paper – “complexity frequently takes the form of hierarchy, and that hierarchic systems have some common properties that are independent of their specific content” (Simon, 1962)

3.  Simon defines as a system that is composed of interrelated subsystems, where each subsystem is also hierarchical and continues until broken down to elementary subsystems  In a hierarchic formal organization, each complex system has a “boss” and subordinate subsystems  Each subsystem is also a boss for it’s subordinate subsystems  This continues until subsystems are at the lowest fundamental level

4.  Formal Organizations (business firms, governments, universities, etc.)  However, not the only type of social hierarchy  Families villages tribes

5.  Cell as the basic building block  Cells tissues organs systems  Cell nucleus, cell membrane, microsomes, etc.  Span of Control/Span of a system  Flat hierarchy if a system has a wide span at a given level vs. the next level  Most of paper looks at hierarchies of moderate span  Hierarchical physical and biological systems usually defined in spatial terms where social is mostly defined by interaction

6.  Systems of human symbolic production  Books chapters paragraph sentence phrases words  Music movements parts themes

7.  Parable of two watchmakers (Tempus and Hora)  Both make fine watches of 1K parts each, Hora prospers, Tempus fails and loses his shop  Both have to pause intermittently to answer customer calls  Hora develops subassembly process allowing him to make watches much faster, Tempus must start over each time he is interrupted  Simon uses as lead-in to biological evolution

8.  Numerical estimate derived from the parable cannot be used directly but the lesson is that the “time required for the evolution of a complex form from simple elements depends critically on the numbers and distribution of potential intermediate stable forms”  Watchmaker parable theory assumes no teleological mechanism (complex forms can arise at random)  Not all large systems are hierarchical (i.e. polymers)  Most biological systems require some form of energy source  The existence of stable intermediate forms on the evolution of complex forms is significant

9.  Usually trial and error, but indications of progress create selective trial and error (this is optimal)  Partial results progressing towards the goal, plays the role of a stable subassembly  Safe problem – cue aides in finding combination  Points to the conclusion that human problem solving is “nothing more than varying mixtures of trial and error and selectivity”  Two basic kinds of selectivity  Various paths or combinations are tried and consequences noted  Previous experience (example is reproduction in organic systems)  Conclusion is that if complex systems have time to evolve they will most likely be hierarchic

10.  Interactions among subsystems distinguished from interactions within subsystems  Decomposable subsystem when inter-subsystem force is negligible compared to force between subsystems (rare gas example)  Nearly decomposable system when interaction between subsystems is weak but not negligible  Summary 2 part proposition:  “Short-run behavior of each of the component subsystems is approximately independent of the short-run behavior of the other components”  “In the long run, the behavior of any one of the components depends in only an aggregate way on the behavior of the other components”

11.  Span is sometimes broad, sometimes narrow  Critical consideration is the extent to which interaction between two (or more) subsystems excludes interactions with the others  Physical example – gas  Social example – conversation vs. mass communication

12.  Hierarchies have property of near decomposability  Intra-component linkages are generally stronger than inter-component linkages

13.  The fact that many complex systems are nearly decomposable and hierarchic enables us to understand and describe them  Other complex systems that are not hierarchic may escape observation and may cause us to believe that most complex systems are hierarchic  Hierarchic systems generally contain redundancy  Usually composed of a few types of subsystems in various arrangements  Are often nearly decomposable  By recoding, the redundancy in a complex system can be made understandable and clear

14.  State description – characterize the world as sensed (pictures, blueprints, most diagrams, chemical structural formulas)  Process descriptions – characterize the world as acted upon (recipes, differential equations, equations for chemical reactions)  Distinction between these two descriptions defines the “basic condition for the survival of adaptive organisms”  Evidence that human problem-solving is a form of means-end analysis that discovers a process to reach a goal (find the process to get from an existing state to a desired state)

15.  Evolution of complexity does not imply self- reproduction (e.g. atoms of high atomic weight and inorganic molecules)  If the description of an object is sufficiently clear and complete, the description provides the necessary information to reproduce the object

16.  Well-known biology generalization  Individual organism in its development goes through stages which resemble ancestral forms  Shows that one way to solve a complex problem is to reduce it to a previously solved problem, this may lead to a solution to the new problem  Concept be applied to problems outside of biology  Partial recapitulation may be the best route leading to advanced knowledge

17.  “How complex or simple a structure is depends upon the way we describe it”  “Most complex structures are enormously redundant”, this redundancy can used to simplify its description  Dynamic laws, expressed as differential or difference equations have played a major role in the development of modern science  The correlation between state and process description is fundamental to the capacity of an adaptive organism to act on its environment

18. Simon, H.A. [1962]. "The Architecture of Complexity". Proceedings of the American Philosophical Society, 106: pp. 467-482.